Electronic clock

ABSTRACT

In detecting power generation of an electronic timepiece having a conventional power generating unit, voltage output by the power generating unit is limited by output from a storage unit since the power generating unit and the storage means are connected when the power generation state is detected, and voltage equal to or larger than voltage output from the storage unit cannot be detected. An electronic timepiece is provided which can overcome the problem and can check an operation of the power generating unit securely irrespective of the state of the storage means.  
     In an electronic timepiece driven by power stored from a power generating unit ( 1 ) into a storage unit ( 4 ), the electronic timepiece includes a power generation detecting unit ( 2 ) that detects a power generation state of the power generating unit ( 1 ) and a switch unit ( 7 ) that separates the power generating unit ( 1 ) and the storage unit ( 4 ) when the power generation state of the power generating unit ( 1 ) is detected. In this case, the switch ( 7 ) between the power generating unit ( 1 ) and the storage unit ( 4 ) is controlled to OFF so that the output from the power generating unit ( 1 ) cannot be limited by the output from the storage unit ( 4 ).

TECHNICAL FIELD

The invention relates to an electronic timepiece having a powergenerating unit and being driven by power generated by the powergenerating unit, and, more specifically, it relates to a technology fordetecting a power generation state of the power-generating unit andinforming the detection result.

BACKGROUND ART

In recent years, electronic timepieces each of which includes a powergenerating unit for saving efforts of battery changes required inconventional electronic timepieces to enhance the convenience of usersand which is driven by power generated by the power generating unit havebeen developed and commercially available.

In an electronic timepiece including a power generating unit, whetherthe power generating unit is normally operating or not, whether a pathfor feeding power generated by the power generating unit to theelectronic timepiece is securely connected or not, and so on must bechecked in production steps in order to secure basic operations as thepower-generating timepiece.

Conventionally, for an electronic timepiece, a technology for outputtingmicropulses to a motor driver circuit based on a power generationdetection signal from a power generation detecting unit in accordancewith an operation by an external operating member has been proposed bythe present applicant as a unit for performing such functional checks(see Patent Document 1, for example).

Patent Document 1:

-   -   WO 02/23285 A1 (Pages 7 to 10 and FIGS. 1 and 19)

The conventional technology will be described below with reference toFIG. 3 of the present application roughly showing a construction ofdetection of power generation of a power generating unit based on FIGS.1 and 19 in Patent Document 1.

In the conventional example in FIG. 3, when a state is attained that anexternal operating member 56 such as the winding knob is pull out, thepower generation state of a power generating unit 50 is detected by apower generation detecting unit 52. When the power generating unit 50 isat the power generation state, microcurrent is output from a micropulsegenerating unit 57 to a motor coil (not shown) through a motor drivercircuit (not shown) A checker can check that the power generating unit50 is generating power by detecting a change in magnetic field occurringin a motor coil upon output of microcurrent through the visual check ofmovement of an external device such as a second hand attached to a train(both of which are not shown) connecting to a motor or through a tester.

By using this technique, whether a power generating unit is normallyoperating in a finished timepiece or not and whether the powergenerating unit and the electronic timepiece are normally connected ornot can be checked, and the most basic operations as a power generatingtimepiece can be secured easily.

Next, problems of the power generation detecting method in conventionalexamples will be described with reference to FIG. 3.

In a conventional example, the power generating unit 50 and a storageunit 54 are connected directly or through an anti-backflow diode 64.Generally, since the output impedance of the power generating unit 50exhibits a higher value than that of the internal impedance of thestorage unit 54, the voltage occurring across the storage unit 54exhibits a substantially constant value in accordance with a voltagevalue output from the storage unit 54 irrespective of the presence ofthe power generation of the power generating unit 50.

Furthermore, as indicated in ( ) in FIG. 3, when the anti-backflow diode64 is provided between the power generating unit 50 and the storage unit54 and while the power generating unit 50 is not generating power, thevoltage of the power generating unit 50 is zero (0). On the other hand,while the power generating unit 50 is generating power, the voltage,which is a sum of an amount of a drop in voltage caused when a currentvalue caused when the power generating unit 50 generates power is fed tothe anti-backflow diode 64 and a voltage value output from the storageunit 54, occurs across the power generating unit 50.

In both cases, voltage occurring across the power generating unit 50depends on voltage output from the storage unit 54 and is originally adifferent value from that of the power generation voltage that the powergenerating unit 50 generates. According to the conventional technique,the presence of the connection of an electronic timepiece including thepower generating unit 50 and storage unit 54 and whether power having avalue equivalent to that of voltage output by the storage unit isgenerated or not could be checked, but whether the power generating unit50 is generating the originally expected power generation voltage or notcould not be checked.

In order to charge electric energy generated by the power generatingunit 50 into the storage unit 54, the voltage generated by the powergenerating unit 50 must be larger than the voltage output from thestorage unit 54. However, the storage unit 54 generally tends to have apotential increasing in accordance with an amount of stored power.Therefore, in order to have the storage unit 54 fully charged, the powergeneration voltage of the power generating unit 50 must be larger thanthe voltage output when the storage unit 54 is fully charged.

For measurement that satisfies the above-described requirements, anoperation of detecting power generation must be performed by detachingthe storage unit 54 or by fully charging the storage unit 54. However,in a process for manufacturing an electronic timepiece, the examinationsunder those states increase the number of man-hours and/or increase themanufacturing costs. In this way, for checking operations of the powergenerating unit 50, the conventional technology has problems thatsufficient examinations cannot be performed or that a large amount ofefforts is required for performing sufficient examinations.

It is an object of the invention is to provide an electronic timepiece,which can overcome the above-described defects and can securely checkoperations of a power generating unit irrespective of the state of apower storage unit.

DISCLOSURE OF THE INVENTION

In order to achieve the object, the principle of an electronic timepieceaccording to the invention is as follows.

In an electronic timepiece driven by electric energy generated by apower generating unit, the electric timepiece includes a storage unitconnected with the power generating unit in parallel through anelectronic switch, a control unit that controls the electronic switch, apower generation detecting unit that detects a power generation state ofthe power generating unit, an informing unit that informs a detectionresult of the power generation detecting unit to the outside, and anexternal operating member. In this case, the external operating memberis operated so that the power generation detecting unit can go intoaction while a power generation detecting operation is performed under acondition that the electronic switch is turned off by the control unitand the result is informed to the outside through the informing unit.Thus, an electronic timepiece can be provided which can check anoperation of the power generating unit securely irrespective of thestate of the storage unit. Furthermore, whether the power generationstate of the power generating unit at a predetermined power generationstate satisfies a desired value or not can be examined simply and withstability.

Furthermore, a first resistor and second resistor and second electronicswitch unit, which are connected in series, are connected to the powergenerating unit in parallel, the second electronic switch unit iscontrolled to ON at the same time that the power generation detectingunit goes into action through the external operating member, and in thatthe input of the power generation detecting unit is connected at themidpoint between the first resistor and the second resistor. Thedivision of voltage by the first resistor and second resistor allows thedetection of power generation voltage generated by the power generatingunit, which is equal to or larger than voltage output from the storageunit.

Furthermore, in an electronic timepiece driven by electric energygenerated by a power generating unit, the electric timepiece includes afirst storage unit connected with the power generating unit in parallel,a second storage unit connected with the power generating unit inparallel through an electronic switch, a control unit that controls theelectronic switch, a power generation detecting unit that detects apower generation state of the power generating unit, an informing unitthat informs a detection result of the power generation detecting unitto the outside, and an external operating member. In this case, theexternal operating member is operated so that the power generationdetecting unit can go into action while a power generation detectingoperation is performed under a condition that the electronic switch isturned off by the control unit and the result is informed to the outsidethrough the informing unit. Thus, even after the electronic switch isturned OFF, the voltage detecting unit can operate by using chargesstored in the first storage unit, and stable detection of powergeneration can be performed thereby.

The first storage unit has a smaller amount of stored power than that ofthe second storage unit. Thus, a simple and temporary storage unit suchas a capacitor can be used as the first storage unit.

Furthermore, the power generation detecting unit detects a powergeneration state of the power generating unit by detecting voltage ofthe first storage unit. Thus, voltage of the voltage detecting unit canbe detected by using charges stored in the first storage unit, andstable detection of power generation can be performed thereby.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial block diagram of an electronic timepiece showing afirst example of the invention.

FIG. 2 is a partial block diagram of an electronic timepiece showing asecond example of the invention.

FIG. 3 is a partial block diagram of a conventional electronic timepiecehaving a power generating unit.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the invention will be described below in detail withreference to drawings. FIG. 1 is a partial block diagram of anelectronic timepiece indicating a first example of the invention.

FIG. 1 includes a power generating unit 1, a power generation detectingunit 2, a control circuit 3, a storage unit 4, an informing unit 5, anexternal operating member 6, an n-channel transistor (electronic switch)7, a first resistor 8 a, a second resistor 8 b, and a p-channeltransistor (second electronic switch unit) 9. In this embodiment, partsrelating to a timepiece among construction elements relating to anelectronic timepiece such as an oscillator circuit, frequency dividercircuit, motor driver circuit and motor in a needle-driven electronictimepiece, for example, are omitted. These components of the electronictimepiece operate by using power from the storage unit 4 according tothis embodiment.

When the external operating member 6 is operated and a power generationdetecting state is attained thereby, a control signal 31 from thecontrol unit 3 exhibits H, and the power generation detecting unit 2goes into action. Furthermore, the n-channel transistor 7 is turned offsince the gate is turned to L through an inverter 32. Furthermore, thep-channel transistor 9 is turned on since the gate is turned to Lthrough the inverter 32. When the power generating unit 1 is at thepower generation state under this condition, power generation voltage V1occurs across the power generating unit 1. The power generation voltageV1 is divided by the first resistor 8 a and second resistor 8 b and isinput, as detection voltage Vd, to the power generation detecting unit2.

The power generation detecting unit 2 compares the detection voltage Vdand predefined reference voltage Vr, and, if Vd>Vr, turns a powergeneration detecting signal 21 to H. When the power generation detectingsignal 21 is turned to H, the informing unit 5 performs an operation forinforming that the power generating unit 1 is at the power generationstate to the outside.

Here, as a reference for determining whether the power generating unit 1is at the power generation state or not, if the power generation voltageV1 exhibits a value equal to or larger than an maximum voltage valueVmax (such as a voltage value upon fully charged) that the storage unit4 can output, the fact that the power generating unit 1 is operatingnormally can be determined. In this case, the value resulting from thedivision of the voltage value Vmax by the first resistor 8 a and secondresistor 8 b may be defined as a reference signal Vr.

As described above, since voltage occurring in the power generating unit1 can be detected independently from the voltage of the storage unit 4according to this embodiment, a performance desired as a powergenerating timepiece can be secured in the simple way.

While the external operating member 6 and informing unit 5 are notspecifically described in this embodiment, constructions thereof can befreely selected in accordance with a form and/or specification of anelectronic timepiece. While, in the above-described Patent Document 1,the winding switch, push switch or the like may be used as the externaloperating member 6 and micropulses or the like output from aneedle-driven motor may be used as the informing unit 5, thesecomponents can be apparently used to implement the operating member 6and/or informing unit 5.

Similarly, the way of operating and controlling the power generationdetecting unit 2 and so on, n-channel transistor 7 and p-channeltransistor 9 in response to the operating member 6 can be selected asrequired. In other words, a form suitable for a user can be freelyselected such as performing a power generation detecting operation onlyfor a predetermined period of time after the external operating member 6is operated.

According to the above-described first embodiment, since the controlunit 3 and power generation detecting unit 2 are driven by voltagesupplied from the storage unit 4, the power generation voltage V1generated by the power generating unit 1 is divided by the resistor 8 aand resistor 8 b in order to detect voltage equal to or larger thanvoltage output from the storage unit 4. In other words, in the firstexample of the construction in FIG. 1, while the power generating unit 1outputs V1, the power generation detecting unit 2 and control unit 3operate at voltage (V4, for example) output by the storage unit 4.

If V1≦V4, the power generation detecting unit 2 that measures V1operates at voltage V4 higher than V1 and can therefore measure V1directly.

However, if V1>V4 (highly possible in the invention having the powergenerating unit 1 and the storage unit 4 separately), the powergeneration detecting unit 2 that is driven by V4 cannot directly measureV1 that is higher voltage than V4.

Therefore, V1 is resistance-divided by 8 a and 8 b such that voltagethat is always measurable even when V1>V4 (that is, Vd≦V4) can bemeasured.

However, the detecting method of the power generation detecting unit isnot limited to the present method.

A second embodiment of the invention will be described below withreference to FIG. 2. The description on elements exhibiting the samedetails as those in FIG. 1 will be omitted. FIG. 2 is a block diagramshowing a partial construction of an electronic timepiece of the secondembodiment and includes a voltage detecting unit 10 that is a powergeneration detecting unit, a diode 11, and a capacitor (first storageunit) 12.

When the external operating member 6 is operated and the powergeneration detecting state is attained thereby, a control signal 31 fromthe control unit 3 exhibits H, and the voltage detecting unit 10 goesinto action. Furthermore, the n-channel transistor 7 is turned off sincethe gate is turned to L through the inverter 32. When the capacitor 12is detached from the storage unit 4 since the n-channel transistor 7 isturned off, current generated in the power generating unit 1 is fed intothe capacitor 12 through the diode 11. Since the capacitor 12 has alower capacitance than that of the storage unit 4, potentialsthereacross rise in a shorter period of time. Thus, the voltage value isa value resulting from the subtraction of a voltage drop VF in the diode11 from the power generation voltage V1 of the power generating unit 1.

The voltage detecting unit 10 turns a power generation detecting signal21 to H when voltage input thereto is equal to or larger than predefinedvoltage. The informing unit 5 performs an operation for informing thatthe power generating unit 1 is at the power generation state to theoutside when the power generation detecting signal 21 is turned to H.

Since the voltage detecting unit 10 used here is connected with thestorage unit 4 in parallel when the n-channel transistor 7 is ON, thevoltage detecting unit 10 can be also used for checking a storage stateof the storage unit 4 such as whether voltage exceeds the rated voltageof the storage unit 4 or not.

The capacitor 12 is used for operating the voltage detecting unit 10with stability when the storage unit 4 is detached therefrom, and thediode 11 plays a role in peak holding of power generation voltage fromthe power generating unit 1. In this case, both of the capacitor 12 anddiode 11 are components for performing operations of this embodimentwith stability.

When a small amount of power is generated by the power generating unit1, for example, the voltage detecting unit 10 is cut off from powersupply and is disabled without the capacitor 12 and diode 11.

When the capacitor 12 and diode 11 are connected thereto as shown inFIG. 2, the capacitor 12 is charged to the substantially same potentialas that of the storage unit 4 immediately before the n-channeltransistor 7 is turned off. Thus, even when the n-channel transistor 7is turned off, the voltage detecting unit 10 can operate for a whilewith charges stored in the capacitor 12, and stable detection of powergeneration can be therefore performed irrespective of the presence ofpower generation.

The first resistor 8 a, second resistor 8 b and p-channel transistor 9shown in the first example are not described and are omitted in thesecond example since a potential equal to or larger than power supplyvoltage of the power generation detecting unit 10 does not have to bedetected because the power supply potential of the voltage detectingunit 10 varies in accordance with the potential output from the powergenerating unit 1 in the second embodiment. In other words, since thevoltage detecting unit 10 is driven by voltage (V1+VF) of the capacitor12 to be detected thereby in the second example having the constructionin FIG. 2, the detection can be performed without resistance division.

As described above, according to the first and second examples, in anelectronic timepiece including a power generating unit and beingoperated by electric energy generated by the power generating unit,whether a power generation state from the power generating unit at apredetermined power generation state satisfies a desired value or notcan be examined in the simple way and with stability.

INDUSTRIAL APPLICABILITY

As described above, an electronic timepiece that is operated by electricenergy generated by a power generating unit according to the inventioncan check an operation of the power generating unit with stability andsimply, which can contribute to enhancement of the productivity.

1. An electronic timepiece driven by electric energy generated by powergenerating means, the electric timepiece characterized by comprisingstorage means connected with the power generating means in parallelthrough an electronic switch, control means that controls the electronicswitch, power generation detecting means that detects a power generationstate of the power generating means, informing means that informs adetection result of the power generation detecting means to the outside,and an external operating member, wherein the external operating memberis operated so that the power generation detecting means can go intoaction while a power generation detecting operation is performed under acondition that the electronic switch is turned off by the control meansand the result is informed to the outside through the informing means.2. An electronic timepiece according to claim 1, characterized in that afirst resistor and second resistor and second electronic switch means,which are connected in series, are connected to the power generatingmeans in parallel, the second electronic switch means is controlled toON at the same time that the power generation detecting means goes intoaction through the external operating member, and in that the input ofthe power generation detecting means is connected at the midpointbetween the first resistor and the second resistor.
 3. An electronictimepiece driven by electric energy generated by power generating means,the electric timepiece characterized by comprising first storage meansconnected with the power generating means in parallel, second storagemeans connected with the power generating means in parallel through anelectronic switch, control means that controls the electronic switch,power generation detecting means that detects a power generation stateof the power generating means, informing means that informs a detectionresult of the power generation detecting means to the outside, and anexternal operating member, wherein the power generation detecting meanscan go into action through the external operating member while a powergeneration detecting operation is performed under a condition that theelectronic switch is turned off by the control means and the result issent to the outside through the informing means.
 4. An electronictimepiece according to claim 3, characterized in that the first storagemeans has a smaller amount of stored power than that of the secondstorage means.
 5. An electronic timepiece according to claim 3 or 4,characterized in that the power generation detecting means detects apower generation state of the power generating means by detectingvoltage of the first storage means.